Cass Sunstein is a professor at Harvard Law School, and a leading constitutional scholar. He recently gave a talk at The Concord Bookshop on his latest book, Impeachment: A Citizens Guide. Needless to say, there was standing room only. We left a little early because it was late, would soon be getting dark, and we had a ways to travel. Sadly, we missed the book signing, which would have been a great photo opportunity.